This invention relates to a method and apparatus for entering digital data into a display timer or clock.
In the past, the most prevalent device for transferring data from an operator into a data processing system has been a keyboard. Although the keyboard is universally used for entering data, rotary switches with discrete positions and thumbwheel switches with discrete positions have also been used in certain specific applications. However, all of these devices inherently require relatively expensive hardware. This drawback is especially disadvantageous in a highly competitive market such as the household appliance market.
Another type of device which is relatively inexpensive but inconvenient to use is an operator controlled oscillator which cycles a system through each of the digital states allowed by the system until the desired digital number appears on the display. This type of input is most commonly used to set the time on digital clocks. However this device is not well suited for other data entry applications where essentially random data is to be entered due to the inconvenience of cycling through all of the possible states and then stopping exactly on the desired state.
Therefore, it can be appreciated that a data entry device and method which is both inexpensive and convenient to use is highly desirable.
Accordingly, an object of this invention is to provide an inexpensive apparatus and method to enter data into a digital timer or clock.
It is another object of this invention to provide a data entry apparatus and method which utilizes an analog-to-digital converter which has a conversion error in excess of the maximum data entry system error.
Yet another object of this invention is to provide a digital entry system which holds the input time while the initial time is being processed so that the original time can be reentered again without operator adjustment.